My high school cross country and track teams are not reputable at all. We are not a good team (distance-wise) and have a few sprinters who are decent. My mileage had never been above 40mpw, so the summer before my senior year of cross country I trained by doing 60mpw. I felt fine all summer but when the school year came I was getting less sleep and eating less, so I got injured. My coach then said that “you only have so many miles in your legs” and that I did too much. To what extent is it true that your legs only have a finite number of miles on them?